Illumination unit and display apparatus using the same

Abstract

An illumination unit includes LEDs and a tabular light guide plate having a light emitting surface for emitting light from the LEDs as planar light, wherein a recessed portion is formed in the opposite surface of the light emitting surface of the light guide plate, and the LED is provided in the recessed portion so that the optical axis of the LED becomes parallel to the light emitting surface of the light guide plate. Here, a dimming pattern is provided at a location corresponding to the LED of the light emitting surface of the light guide plate, and furthermore a first light guide pattern is provided on the light emitting surface of the light guide plate and a second light guide pattern is provided on a rear surface that is a reflective surface.

The invention claimed is: 
     
       1. An illumination unit, comprising a light emitting element as a light source and a tabular light guide plate having a light emitting surface for emitting light from the light source as planar light, wherein a recessed portion is formed in an opposite surface of the light emitting surface of the light guide plate, and the light emitting element is provided in the recessed portion so that an optical axis of the light emitting element becomes parallel to the light emitting surface of the light guide plate;
 wherein a dimming pattern is provided on the fight emitting surface of the light guide plate at a portion positionally corresponding to the tight emitting element; 
 wherein a first light guide pattern is provided on the light emitting surface of the light guide plate; and 
 wherein a second light guide pattern is provided on a rear surface of the light guide plate. 
 
     
     
       2. The illumination unit according to  claim 1 , wherein the light emitting element is an LED. 
     
     
       3. The illumination unit according to  claim 1 , wherein the dimming pattern is formed by printing. 
     
     
       4. The illumination unit according to  claim 1 , wherein a plurality of the light emitting elements are arranged along a longer direction of the recessed portion, and wherein a third light guide pattern is formed between the light emitting elements on the light emitting surface of the light guide plate. 
     
     
       5. The illumination unit according to  claim 4 , wherein the first light guide pattern and the third light guide pattern are integrally formed on the light emitting surface of the light guide plate. 
     
     
       6. The illumination unit according to  claim 1 , wherein a plurality of the light emitting elements are arranged along a longer affection of the recessed portion, and wherein a fourth light guide pattern is formed between the light emitting elements on the rear surface of the light guide plate. 
     
     
       7. The illumination unit according to  claim 5 , wherein the second light guide pattern and the fourth light guide pattern are integrally formed on the rear surface of the light guide plate. 
     
     
       8. The illumination unit according to  claim 1 , wherein thicknesses of the dimming pattern and the first light guide pattern provided on the light emitting surface of the light guide plate are different from each other. 
     
     
       9. The illumination unit according to  claim 8 , wherein the first light wide pattern comprises a plurality of dots with different thicknesses. 
     
     
       10. The illumination unit according to  claim 1 , wherein a print range of the light guide pattern provided in the light guide plate is set within 10 mm or more from an outer periphery of the light guide plate. 
     
     
       11. A display apparatus using the illumination unit according to  claim 1  as a back light.